Speed ratio controller and control method of toroidal continuously variable transmission

摘要

A speed ratio of a toroidal continuously variable transmission is varied by a step motor (4). The step motor (4) is responsive to a command signal Astep which a controller (61) outputs corresponding to a target speed ratio. The controller (61) is programmed to initialize the command signal Astep when it is activated while the vehicle is running (S152) such that the command signal coincides with an actual operation position of the step motor (4). The controller (61) is further programmed to limit the command signal, after performing this initialization, within a first limiting range which is narrower than a second limiting range corresponding to a physical operation limit of the step motor (4) (S168, S170). By applying such a limitation to the command signal, the command signal is prevented from exceeding the operation limit of the step motor (4) even when a torque shift error is introduced into the command signal by the initialization while the vehicle is running.